Antiinflammatory aspects of exogenous arachidonic acid.

Resident rat peritoneal macrophages (M0) were more active in metabolising exogenous arachidonic acid (AA) to prostaglandin E2 (PGE2) than starch elicited cells. Basal levels of cAMP were lower in elicited macrophages than in resident cells but the adenyl cyclase of elicited macrophages was much more readily stimulated by cyclooxygenase products formed from exogenous AA than resident cells. AA injected into carrageenin sponge granulomas reduced the severity of the inflammation in a dose related manner.